Commonly, drywall corner beads, drywall seam-covering devices, and other drywall corner-finishing accessories are extruded from a substantially rigid, polymeric material, such as polyvinyl chloride. As exemplified in Failla et al. U.S. Pat. No. 4,288,016, such a corner bead has two strips joined by an integral, generally U-shaped lip, which functions to guide a drywall-finishing blade used to apply drywall-finishing material over the strips and adjoining drywall panels and which lends limited flexibility to such a corner bead.
However, as exemplified by Swanson U.S. Pat. No. 3,444,657, Lamb U.S. Pat. No. 4,313,991, and Hoffmann, Sr., U.S. Pat. No. 4,835,925, it is known for such accessories to be sufficiently flexible to be selectively useful at either inside or outside corners. As disclosed in the Swanson and Lamb patents, such accessories have grooves or notches to provide such flexibility. Along with embodiments of similarly grooved or notched accessories, the Hoffmann, Sr., patent discloses embodiments having strips of substantially rigid, polymeric material joined by hinges of substantially flexible, polymeric material.
Moreover, U.K. Patent Application GB 2,166,771A, as published May 14, 1986, discloses a corner molding of related interest. The corner moulding is flexible at three areas of reduced wall thickness.
This invention has resulted from efforts to improve such drywall corner-finishing accessories.